RP05/RP06 Device Control Logic

This "RP05/RP06 Device Control Logic Maintenance Manual" (EK-RP056-MM-001) from Digital Equipment Corporation, published in December 1975, provides detailed information on the Device Control Logic (DCL) incorporated in the RP05 and RP06 Disk Drives.

Key aspects covered include:

1. Introduction: Describes the DCL's role in interpreting and executing commands, supporting dual controller operation, and its compatibility with PDP-11, PDP-15, and DECsystem-10 systems (handling 16- or 18-bit data formats). It notes the RP06 has almost double the storage capacity of the RP05 but shares an identical DCL interface.
2. Physical Description: Details the DCL's physical components, including its various printed circuit boards (Hex PCBs like Registers, Dual Port, Seek and Search, Synchronous Transfer, Error Correction; and MASSBUS/MDLI interface PCBs), power supply (H764), and power monitor.
3. DCL Functional Description: Explains core operations:
   • Dual Controller Operation: How two controllers can access the drive on a "first-come, first-serve" basis.
   • Read/Write Data Transfers: Commands for formatting disks (Write Header and Data), writing data, reading headers and data, and read/write check operations.
   • Disk Addressing: Commands like Seek (for head positioning), Search (for optimizing pack revolution time), and Offset (for fine-tuning head position). It also covers "implied seek" during data transfers.
   • Interface Registers: Categorizes and briefly describes the 16 registers used for control, status, maintenance, error information, and disk addressing within the DCL.
   • Error Correction Capability: Details the DCL's ability to detect and provide information for correcting data field errors during read operations.
4. Theory of Operation: This extensive section delves into the detailed workings of the DCL, including:
   • Asynchronous and synchronous data transfers.
   • In-depth explanations of disk addressing logic (cylinder, track, and sector addressing).
   • Description of MASSBUS and MDLI (Drive) interface signals.
   • A comprehensive command repertoire, categorizing control, data transfer, housekeeping (e.g., NO-OP, Drive Clear, Pack Acknowledge), and mechanical movement commands (e.g., Seek, Recalibrate, Unload).
   • Detailed flow and timing diagrams for various operations like writing headers, comparing headers, writing data, and reading data.
   • Error handling and error correction code (ECC) processes.
5. Service and Maintenance: States that no special adjustment procedures are necessary for DCL servicing. Replacement procedures primarily involve correctly setting dual-in-line rocker switches for device addresses on the DP hex PCB. Maintenance is primarily achieved through diagnostic programs, with references to other manuals for specific test objectives.
6. Appendix: Provides descriptions and diagrams for various integrated circuits utilized in the DCL.

The manual serves as a comprehensive guide for understanding the logic and operations of the RP05/RP06 Disk Drive's control system for maintenance purposes.